<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <meta name="计数器" content="计数器">
        <meta description="计数器" content="计数器">
        <title>计数器</title>
        <style>
            * {
                margin: 0;
                padding: 0;
            }
            ul {
                list-style: none;
            }
            body {
                counter-reset: month;
            }
            .box {
                counter-reset: day;
                width: 300px;
                margin: 30px auto 0;
                
            }
            .month {
                text-align: center;
            }
            .month::after {
                counter-increment: month;
                content: '第 'counter(month)'月';
            }
            .day>li {
                float: left;
                width: 50px;
                height: 50px;
                text-align: center;
                line-height: 50px;
            }
            .day>li::after {
                counter-increment: day;
                content: counter(day);
            }
            .clearfix::after {
                content: '';
                display: block;
                clear: both;
            }
        </style>
    </head>
    <body>
        <div class="box">
            <h3 class="month"></h3>
            <ul class="day clearfix">
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
            </ul>
        </div>
        <div class="box">
            <h3 class="month"></h3>
            <ul class="day clearfix">
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
            </ul>
        </div>
    </body>
</html>